1. Field of the Invention
The present invention relates to industrial systems, and more particularly to a flexible industrial system with quick change part holding means which can be used to perform many different operations on a wide variety of parts. The embodiment disclosed shows such a flexible industrial system adapted to test many different types of parts using a single piece of test equipment by virtue of having a series of identical pallets for each type of part to be tested which can be quickly on-loaded and offloaded from a means of providing movement between a plurality of stations, such as a rotary index table.
By providing that each in a series of part holding means has means to connect the part holding means to the means of providing movement between stations, means to perform desired operations on parts on the part holding means, and means to quickly connect to said means to perform desired operations, a tremendously flexible test system is provided. An air leak test is an example of one of the many types of tests or operations which may take place in such test system.
2. Description of the Prior Art
The prior art testing systems of which Applicants are aware are either of the conveyor type or rotary type. The conveyor type has a positive or nonpositive conveyor, with a series of dedicated test stands spaced around the conveyor. Each of the test stations can only perform a predetermined fixed operation or sequence of operations, and thus can only test one type of part.
An example of such a conveyor-type test system is disclosed in U.S. Pat. No. 3,648,819 issued to V. G. Converse, III et al. and owned by Applicants' assignee. In operation, the nonpositive conveyor has a series of identical pallets and test parts, and would move them on or off the conveyor to the test stands as needed, depending on a series of mechanical flags.
If, for example, three different types of engines were to be run on a line, three different types of stands may be needed, and if a particular type of engine was not on the line at one time, the stands dedicated to testing that type of part would stand idle. In addition, switching between different types of test parts could not be made because the stand could not accomodate this. For example, a switch from engines to transmissions could not be made. Thus, this test system, although testing engines much faster than previous test stands were able to, and representing a great advance in the art at the time, still left serious problems in the testing art because of the dedicated nature of the test stands.
The advent of the rotary-type testing system, as evidenced by the U.S. Pat. No. 4,285,233 assigned to the Sun Electric Company, did little to alleviate this problem because although it used a rotary index table to conserve space, it still required dedicated test stands, and could only test one type of product at a time, thus having virtually no flexibility whatsoever.
In addition, both the continuous conveyor type, and the rotary index type of test system, because of the fact that they had dedicated test stands and required an entire test, whether a leak test or other type of test, to be conducted in a single stand, required a much greater test time. For example, in a leak test, which requires a fill time, a balance time and then a test time, the total test time for each station was the total of these three times, rather than just the actual test time and, as will be shown, this greatly reduced production rates of these type of stands and greatly increased costs, thus, leaving serious problems in the art for one who had a wide variety of parts to test, and needed flexibility in a test stand, and at the same time needed high production rates.
Applicant's assignee was instrumental in solving some of the problems of the rotary index table type of test system when it produced a twelve station halogen leak test machine in which a part was clamped and sealed in a test chamber, the chamber was evacuated, and the part was pressurized, and a test of the atmosphere of the test chamber was made to find if any gas leaked through the walls of the test part into the chamber.
In this machine, the pressurization, which could correspond to the balance time in a leak test system, took place over two stations. However, even this test machine left serious problems in the art because the fixturing was dedicated to the testing of one single part and, although it could be serviced off-line if a defect developed, one fixture was certainly not interchangeable with another for testing a multitude of types of test parts rapidly and easily as can be done by the present invention. Thus, even this leak testing machine did not produce the flexibility of the present invention.